Relative benefit of TLIF versus PSF stratified by diagnostic indication.

STUDY DESIGN: Case-matched retrospective. OBJECTIVES: The purpose of this study is to compare 2-year health-related quality of life (HRQOL) outcomes of patients who underwent 1-level or 2-level posterolateral spine fusion (PSF) versus transforaminal interbody fusion (TLIF) for degenerative spondylolisthesis, disk pathology, and postdecompression instability. SUMMARY OF BACKGROUND DATA: The optimal surgical technique for patients with spondylolisthesis or other degenerative conditions has not been defined. Historically, PSF was the most common procedure, whereas in recent years TLIF has gained popularity. Although theoretical advantages for TLIF have been outlined, evidence for improved outcomes with the addition of interbody support is limited. METHODS: Patients with degenerative spondylolisthesis, with disk pathology and or postdecompression instability who underwent 1-level or 2-level TLIF and completed 2 years postoperative HRQOL measures were identified from a prospective database. These patients were then propensity-matched to a cohort of PSF patients based on age, number of surgical levels, body mass index, sex, smoking status, workers' compensation status, and preoperative outcome measures including the Oswestry Disability Index, SF-36 Physical Component Summary score, SF-36 Mental Composite Summary score, and back and leg pain scores. This produced 63 matched pairs with degenerative spondylolisthesis, 46 with disk pathology and 32 with postdecompression instability. RESULTS: All patients in both groups for each cohort reported statistically significant improvement in HRQOL scores at 2 years postoperatively compared with baseline. Improvements in the Oswestry Disability Index, SF-36 Physical Component Summary score, and back and leg pain scores within the spondylolisthesis and disk pathology subgroups were similar between patients who had a TLIF compared with those who had a PSF. The postdecompression instability subgroup was the only subgroup in which TLIF outperformed PSF for every outcome measure. CONCLUSIONS: Clinical outcome was not significantly altered with TLIF as compared with PSF in patients with spondylolisthesis or disk pathology. However, TLIF resulted in better outcomes at 2 years postoperatively in patients with postdecompression instability.

Staged circumferential lumbar fusions have less intraoperative complications and shorter operative time with no difference in 30-, 90-, and 1-year complications: a propensity-matched cohort analysis of 190 patients.

BACKGROUND CONTEXT: Circumferential lumbar fusions (cLFs) are becoming more common with increasing and more minimally invasive anterior access techniques. Staging allows reassessment of indirect decompression and alignment prior to the posterior approach, and optimization of OR time management. Safety of staging has been well documented in deformity surgery but has yet to be delineated in less extensive, degenerative cLFs. PURPOSE: The purpose of this study is to compare perioperative complications and outcomes between staged versus single-anesthetic circumferential fusions in the lumbar spine. STUDY DESIGN: Propensity-matched comparative observational cohort. PATIENT SAMPLE: Patients who underwent cLFs for lumbar degenerative disease. OUTCOME MEASURES: In-hospital, 30-day, 90-day, and 1-year complications. METHODS: From 123 patients undergoing single-anesthetic and 154 patients undergoing staged cLF, 95 patients in each group were propensity-matched based on age, sex, BMI, ASA score, smoking, revision, and number of levels. We compared perioperative, 30-day, 90-day, and 1-year complications between the two cohorts. RESULTS: Mean days between stages was 1.58. Single-anesthetic cLF had longer total surgery time (304 vs 240 minutes, p<.001) but shorter total PACU total time (133 vs 196 minutes, p<.001). However, there was no difference in total anesthesia time (368 vs 374 minutes, p=.661) and total EBL (357 vs 320cc, p=.313). Intraoperative complications were nine incidental durotomies in the single-anesthetic and one iliac vein injury in the staged group (9% vs 1%, p=.018). There was no difference of in-hospital (38 vs 31, p=.291), 30-day (16 vs 23, p=.281), 90-day (10 vs 15, p=.391), 1-year complications (9 vs 12, p=.644), and overall cumulative 1-year complications (54 vs 56, p=.883) between the two cohorts. CONCLUSIONS: There is a decrease in total surgical time and intraoperative complications during staged compared with single-anesthetic cLF with no difference in in-hospital, 30-day, 90-day, and 1-year complications between approaches.

Comparison of No Tap (two-step) and tapping robotic assisted cortical bone trajectory screw insertion.

Workflow for cortical bone trajectory (CBT) screws includes tapping line-to-line or under tapping by 1 mm. We describe a non-tapping, two-step workflow for CBT screw placement, and compare the safety profile and time savings to the Tap (three-step) workflow. Patients undergoing robotic assisted 1-3 level posterior fusion with CBT screws for degenerative conditions were identified and separated into either a No-Tap or Tap workflow. Number of total screws, screw-related complications, estimated blood loss, operative time, robotic time, and return to the operating room were collected and analyzed. There were 91 cases (458 screws) in the No-Tap and 88 cases (466 screws) in the Tap groups, with no difference in demographics, revision status, ASA grade, approach, number of levels fused or diagnosis between cohorts. Total robotic time was lower in the No-Tap (26.7 min) versus the Tap group (30.3 min, p = 0.053). There was no difference in the number of malpositioned screws identified intraoperatively (10 vs 6, p = 0.427), screws converted to freehand (3 vs 3, p = 0.699), or screws abandoned (3 vs 2, p = 1.000). No pedicle/pars fracture or fixation failure was seen in the No-Tap cohort and one in the Tap cohort (p = 1.00). No patients in either cohort were returned to OR for malpositioned screws. This study showed that the No-Tap screw insertion workflow for robot-assisted CBT reduces robotic time without increasing complications.

Intra-Operative Hypotension is an Important Modifiable Risk Factor for Major Complications in Spinal Fusion Surgery.

STUDY DESIGN: Retrospective observational cohort. OBJECTIVES: This study explores the impact of Intraoperative hypotension (IOH)on post-op complications for major thoracolumbar spine fusion procedures. SUMMARY OF BACKGROUND DATA: IOH with mean arterial pressure (MAP) < 65 mmHg is associated with post-op acute kidney injury (AKI) in general surgery. In spinal deformity surgery, IOH is a contributing factor to MEP changes and spinal cord dysfunction with deformity correction. METHODS: 539 thoracolumbar fusion cases, > 6 surgical levels and > 3 hours duration were identified. Anesthetic/surgical data included OR time, fluid volume, blood loss, blood product replacement and use of vasopressors. Arterial-line based MAP data was collected at 1 min intervals. Cummulative duration of MAP < 65 mmHg was recorded. IOH within the first hour of surgery vs. the entire case was determined. Post-op course and complications including SSI, GI complications, pulmonary complications, MI, DVT, PE, AKI and encephalopathy were noted. Cumulative complications were grouped as none, 1-2 complications, or >3 complications. RESULTS: There was a significant association between occurrence of complications and duration of IOH within the first hour of surgery (8.2 vs. 5.6 min, P<0.001) and across the entire procedure (28.1 vs. 19.3 min, P=0.008). This association persisted for individual major complications including SSI, acute respiratory failure, PE, ileus requiring NGT and post-operative cognitive dysfunction. Comparison of patients with 0 vs. 1-2 vs. 3 or more complications demonstrated that patients with 3 or more complications had a longer duration of IOH in the first hour of the surgery and that patients who had no complications received less vasopressor than patients who had 1-2 or 3 or more complications. CONCLUSION: This study identifies duration of IOH during the first hour of surgery as a previously unrecognized modifiable risk associated with major complications for multi-level lumbar fusion surgery.

Accuracy of Phantomless Calibration of Routine Computed Tomography Scans for Opportunistic Osteoporosis Screening in the Spine Clinic.

STUDY DESIGN: Diagnostic accuracy study. OBJECTIVE: To establish a simple method of phantomless bone mineral density (BMD) measurement by using preoperative lumbar Computed Tomography (CT) scans, and compare the accuracy of reference tissue combinations to diagnose low BMD against uncalibrated Hounsfield units (HUs). SUMMARY OF BACKGROUND DATA: HUs are used as a measure of BMD; however, associations between HU and T-scores vary widely. Quantitative CT (qCT) scans are more accurate, but they require density calibration with an object of known density (phantom), which limits feasibility. As an emerging technique, phantomless (internal) calibration of routine CT scans may provide a good opportunity for screening. METHODS: Patients who were scheduled to undergo lumbar surgery, with a preoperative CT scan, and a dual-energy x-ray absorptiometry (DXA) scan within six months were included. Four tissues were selected for calibration: subcutaneous adipose (A), erector spinae (ES), psoas (P) and aortic blood (AB). The HUs of these tissues were used in linear regression against ground-truth values. Calibrations were performed by using two different internal tissues at a time to maintain simplicity and in-office applicability.Volumetric bone mineral densities (vBMD) derived from internally calibrated CT scans were analyzed for new threshold values for low bone density. Areas under the curve (AUC) were calculated with 95% confidence intervals (CI). RESULTS: 45 patients were included (M/F=10/35, mean age:63.3). Calibrated vBMDs had stronger correlations with DXA T-scores when compared with HUs, with L2 exhibiting the highest coefficients. Calibration by using A and ES with the threshold of 162 mg/cm3 had a sensitivity of 90% in detecting low BMD (AUC=0.671). CONCLUSIONS: This novel method allows simple, in-office calibration of routine preoperative CT scans without the use of a phantom. Calibration using adipose and erector spinae with a threshold of 162 mg/cm3 is proposed for low bone density screening with high sensitivity (90%). LEVEL OF EVIDENCE: Level III.

Comparison of Complication Rates Between Transforaminal Interbody Fusion and Anteroposterior Fusion for One- or Two-Level Degenerative Lumbar Spine Surgery: A Propensity Score Matched Analysis.

Introduction Although transforaminal interbody fusion (TLIF) and anterior lumbar interbody fusion (ALIF) combined with posterior fusion (AP) have similar fusion rates, it is unclear if choice of approach has an impact on post-operative complications. Research question Is the incidence of residual leg and/or back pain requiring additional treatment after one- or two-level TLIF and AP similar? Material and methods Adult patients who underwent one- or two-level TLIF or AP for degenerative pathology were identified and matched using age, sex, body mass index (BMI), American Society of Anesthesiologists (ASA), insurance status, smoking status, revision and number of levels fused. The incidence of radicular leg and back pain requiring emergency department visit/readmission or same level surgical intervention was compared between the two groups. Results Of the 319 TLIF and 288 AP cases, 119 cases in each cohort were matched. TLIF patients had shorter operative times (203 min vs 258 min, P<0.001) and hospital stays than the AP patients (3.76 days vs 4.98 days, P<0.001). The incidence of residual leg pain (7 vs 5, P=0.769) and back pain (13 vs 15, P=0.841) was similar between the two groups. Except for constipation, which was more common in the AP group, the incidence of complications was similar between the two groups. Conclusions Patients undergoing one- or two-level TLIF showed shorter operative time and hospital stay compared with those undergoing AP. The incidence of leg radiculopathy and back pain was similar between the two groups. Surgeons should consider these findings as part of the decision-making process regarding which approach to use in patients requiring a lumbar interbody fusion.

Proximal Junctional Degeneration and Failure Modes: A Novel Classification and Clinical Implications.

STUDY DESIGN: Case-control study. OBJECTIVE: To introduce a classification system that will include the major types of degenerative changes and failures related to the proximal junction, and to determine the clinical course and characteristics for the different types of proximal junctional degeneration (PJD). SUMMARY OF BACKGROUND DATA: Proximal junctional kyphosis (PJK) and failures are well recognized after adult spinal fusion, however, a standardized classification is lacking. METHODS: The proposed system identified four different patterns of PJD: Type 1 (multi-level symmetrical collapse), Type 2 (Single adjacent level collapse), Type 3 (fracture) and Type 4 (spondylolisthesis). A single center database was reviewed from 2018 to 2021. Patients ≥18 years of age, who underwent posterior spinal fusion of ≥3 levels with an upper instrumented vertebral level between T8-L2, and a follow-up of ≥2 years were included. Radiographic measurements, revision surgery and time to revision were the primary outcomes. RESULTS: 150 patients were included with a mean age of 65.1 (±9.8) years and a mean follow-up of 3.2 (±1) years. 69 patients (46%) developed significant degenerative changes in the proximal junction, and were classified accordingly. 20 (13%) were Type 1, 17 (11%) were Type 2, 22 (15%) were Type 3 and 10 (7%) were Type 4. Type 3 had a significantly shorter time to revision with a mean of 0.9 (±0.9) years. Types 3 and 4 had greater preoperative sagittal vertical axis, and Types 1 and 3 had greater final follow-up lumbar lordosis. Bone density measured by Hounsfield units showed lower measurements for Type 3. Types 1 and 4 had lower rates of developing PJK. Type 1 had the lowest revision rate with 40% (types 2, 3 and 4 were 77%, 73% and 80%, respectively, P=0.045). CONCLUSION: This novel classification system defines different modes of degeneration and failures at the proximal junction, and future studies with larger sample sizes are needed for validation. LEVEL OF EVIDENCE: 3.

Predictors of Delayed Clinical Benefit Following Surgical Treatment for Low Grade Spondylolisthesis.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: To investigate what factors predict delayed improvement after surgical treatment of low grade spondylolisthesis. SUMMARY OF BACKGROUND DATA: Lumbar surgery leads to clinical improvement in the majority of patients with low grade spondylolisthesis. Most patients improve rapidly after surgery, but some patients demonstrate a delayed clinical course. METHODS: The Quality and Outcomes Database (QOD) was queried for grade 1 spondylolisthesis patients who underwent surgery who had patient reported outcome measures (PROMs) collected at baseline, 3-, 6- and 12-months, including back and leg pain numeric rating scale (NRS), Oswestry Disability Index (ODI), and EuroQol-5D (EQ-5D). Patients were stratified as "Early responders" reaching MCID at 3 months and maintaining improvement through 12 months and "Delayed responders" not reaching MCID at 3 months but ultimately reaching MCID at 12 months. These two groups were compared with respect to factors which predicted delayed improvement. RESULTS: Of 608 patients enrolled, 436 (72%) met inclusion criteria for this study. Overall, 317 patients (72.7%) reached MCID for ODI at 12 months following surgery. Of these patients, 249 (78.5%) exhibited a rapid clinical improvement trajectory and had achieved ODI MCID threshold by the 3-month postop follow-up. 68 patients (21.4%) showed a delayed trajectory, and had not achieved ODI MCID threshold at 3 months, but did ultimately reach MCID at 12-month follow-up. Factors associated with delayed improvement included impaired preoperative ambulatory status, better baseline back and leg pain scores, and worse 3-month leg pain scores (P<0.01). CONCLUSIONS: The majority of patients undergoing surgery for low grade spondylolisthesis reach ODI MCID threshold rapidly, within the first three months after surgery. Factors associated with a delayed clinical course include impaired preoperative ambulation status, relatively better preoperative back and leg pain, and persistent leg pain at 3 months.

Incidence of revision surgery and patient-reported outcomes within 5 years of the index procedure for grade 1 spondylolisthesis: an analysis from the Quality Outcomes Database spondylolisthesis data.

OBJECTIVE: Some patients treated surgically for grade 1 spondylolisthesis require revision surgery. Outcomes after revision surgery are not well studied. The objective of this study was to determine how revision surgery impacts patient-reported outcomes (PROs) in patients undergoing decompression only or decompression and fusion (D+F) for grade 1 spondylolisthesis within 5 years of the index surgery. METHODS: Patients in the 12 highest Quality Outcomes Database (QOD) enrolling sites with a diagnosis of grade 1 spondylolisthesis were identified and the incidence of revision surgery between the decompression-only and D+F patients were compared. PROs were compared between cohorts requiring revision surgery versus a single index procedure. RESULTS: Of 608 patients enrolled, 409 had complete 5-year data available for this study. Eleven (13.3%) of 83 patients underwent revision in the decompression-only group as well as 32 (9.8%) of 326 in the D+F group. For the entire cohort, patients requiring revision had significantly worse PROs at 5 years: Oswestry Disability Index (ODI) 27.4 versus 19.4, p = 0.008; numeric rating scale for back pain (NRS-BP) 4.1 versus 3.0, p = 0.013; and NRS for leg pain (NRS-LP) 3.4 versus 2.1, p = 0.029. In the decompression-only group, the change in 5-year PROs was not impacted by revision status: ODI 31.9 versus 24.2, p = 0.287; NRS-BP 1.9 versus 2.9, p = 0.325; and NRS-LP 6.2 versus 3.7, p = 0.011. In the D+F group, the change in 5-year PROs was diminished if patients required revision: ODI 19.1 versus 29.1, p = 0.001; NRS-BP 3.0 versus 4.0, p = 0.170; and NRS-LP 2.3 versus 4.6, p = 0.001. CONCLUSIONS: The most common reasons for reoperation within 5 years in the decompression-only group were repeat decompression and instability, whereas in the D+F group the most common reason was adjacent-segment disease. The need for revision resulted in modestly diminished benefit compared with patients with no revisions. These differences were greater in the fusion cohort compared with the decompression-only cohort. The mean PRO improvement still far exceeded minimal clinically important difference thresholds for all measures for patients who underwent a revision surgery.

Clinical and Radiographic Outcomes of Repair of Spondylolitic Spondylolisthesis via Direct Pars Repair.

STUDY DESIGN: A retrospective chart review. OBJECTIVE: The objective of this study is to investigate whether direct pars repair achieves bone healing and symptom relief in patients with spondylolitic spondylolisthesis. SUMMARY OF BACKGROUND DATA: While most cases of spondylolysis can be managed non-operatively, a small percentage of patients require surgical intervention. The outcome of direct pars repair via a standard pedicle-screw with wiring technique is controversial in patients with lumbar spondylolitic spondylolisthesis. METHODS: Medical records of patients who had undergone an open surgical pars repair were retrospectively reviewed. Standard demographic and surgical parameters were collected. All patients underwent a primary repair of the pars with autograft or bone morphogenetic protein and instrumentation using a pedicle-screw with spinous process wiring. At 6-12 months after surgery, patient's pain symptoms and postoperative CT scans were independently reviewed to assess healing; graded as non-union, partial union, or solid union. RESULTS: There were 68 patients identified (33 male and 35 female) with an average age of 18.6 years. Mean estimated blood loss was 139 ml, and mean length of hospital stay was 3.7 days. CT evaluation revealed 35 (52%) solid unions, 21 (31%) partial unions, and 12 (18%) non-unions requiring revisions. Thirty-four (50%) patients had no postop pain, 24 (35%) had mild pain, 10 (15%) had persistent pain. The majority of patients with non-unions on CT had mild or persistent pain. Patients with no or mild pain tended to be younger than those with persistent pain (17.5 years vs 24.6 years, P=0.163). CONCLUSION: This study demonstrated a partial or complete union rate of 82% and a postoperative persistent pain rate of 15%. These figures are comparable to the previous study and this pedicle-screw with wiring technique can be worth trying before interbody fusion for spondylolytic spondylolisthesis to preserve anatomical lumbar motion.

Quantitative Romberg on a Force Plate: Objective Assessment Before and After Surgery for Cervical Spondylotic Myelopathy.

STUDY DESIGN: Longitudinal Observational Cohort. OBJECTIVES: The purpose of this study was to evaluate the utility of Quantitative Romberg measurements as pre- and post-op balance outcome measures. SUMMARY OF BACKGROUND DATA: Cervical Spondylotic Myelopathy (CSM) is characterized by balance deficiencies produced by impaired proprioception. Evaluation is subjective and binary physical exam findings lack the precision to assess postoperative outcome improvement. METHODS: CSM patients were prospectively enrolled to undergo pre- and postoperative Quantitative Romberg tests on a force plate to record center of pressure (COP) motion for 30 seconds with eyes open followed by eyes closed. Revision cases were excluded. Kinematics of COP movement parameters were compared between pre- and postoperative state for each patient. RESULTS: Twenty-seven CSM patients were enrolled and completed both pre/post testing. Mean age was 60.0 years with 13 (48%) males, 9 (33%) smokers. Mean number of surgical levels was 2.48. The minimum mean follow-up was six months. There was a statistically significant improvement in eyes closed after surgery compared to pre-operative for total COP motion (523.44 cm vs. 387.00 cm, P<0.001), average sway speed (17.41 cm/s vs. 13.00 cm/s, P<0.001) and total lateral COP motion (253.44 cm vs. 186.70 cm, P<0.001). There was no statistically significant improvement in mJOA (13.29 vs. 14.29, P=0.28). CONCLUSION: CSM balance findings on Quantitative Romberg testing significantly improves postoperatively in patients with CSM. These findings support this testing as representative of proprioceptive balance deficiencies seen in CSM. Quantitative Romberg may be used as an objective measure of clinical outcome and assist in stratification of surgical interventions, surgery timing and technique.

The influence of preoperative MRI findings on lumbar fusion clinical outcomes.

INTRODUCTION: Spinal fusion as a treatment for degenerative disc disease is controversial. Prior authors have identified various MRI findings as being pain generators, which might help guide patient selection for lumbar fusion procedures. These findings have included disc desiccation, disc contour, high-intensity zone annular disruption, the presence of Modic endplate changes, and disc space collapse. The purpose of this study is to investigate which MRI findings in patients with degenerative disc disease predict clinical improvement with lumbar fusion. METHODS: A single-center surgical database of patients undergoing lumbar fusion was reviewed for patients whose indication for fusion surgery was primary disc pathology. We identified 51 patients (71 disc levels) who had completed 2-year prospectively collected outcomes questionnaires and had preoperative MRIs available for review. NRS (0-10) back and leg pain, Oswestry Disability Index (ODI) and SF-36 Physical Composite Summary scores were obtained preoperatively and at 1- and 2-year follow-up. MRIs were reviewed by three fellowship-trained spine surgeons who were asked to grade them for the following five characteristics: (a) disc desiccation, (b) disc contour, (c) presence of a high-intensity zone (HIZ) annular tear, (d) presence of Modic endplate changes and (e) disc height. Two-year outcome measures were compared to MRI findings to identify which findings correlated with improvement in outcome scores. RESULTS: Statistically significant improvements were noted in back pain, leg pain, SF-36 PCS and ODI in the group overall. Disc desiccation, disc contour, presence of an HIZ lesion, and the presence of Modic endplate changes did not correlate with 2-year outcomes. Disc height was correlated with 2-year change in outcome measures. Discs with preoperative height less than 5 mm demonstrated a 23.4 point ODI improvement compared to 9.2 points for discs >7 mm. Similarly, SF-36 PCS improved 9.5 points in discs <5 mm compared to 0.7 in discs greater than 7 mm. Discs between 5 and 7 mm demonstrated intermediate levels of improvement. CONCLUSIONS: Several commonly utilized MRI criteria proposed as indications for lumbar fusion do not seem to correlate with 2-year improvement in clinical outcomes. Discs which are narrowed and collapsed, preoperatively, demonstrate better improvement at 2 years postoperatively as compared to discs which have maintained disc height. Significant disc space collapse may represent a subset of "degenerative disc disease" which responds more favorably to treatment with fusion.

Postoperative Epidural Hematoma.

Symptomatic postoperative epidural hematomas are rare, with an incidence of 0.10% to 0.69%. Risk factors have varied in the literature, but multiple studies have reported advanced age, preoperative or postoperative coagulopathy, and multilevel laminectomy as risk factors for hematoma. The role of pharmacologic anticoagulation after spine surgery remains unclear, but multiple studies suggest it can be done safely with a low risk of epidural hematoma. Prophylactic suction drains have not been found to lower hematoma incidence. Most symptomatic postoperative epidural hematomas present within the first 24 to 48 hours after surgery but can present later. Diagnosis of a symptomatic hematoma requires correlation of clinical signs and symptoms with a compressive hematoma on MRI. Patients will usually first complain of a marked increase in axial pain, followed by radicular symptoms in the extremities, followed by motor weakness and sphincter dysfunction. An MRI should be obtained emergently, and if it confirms a compressive hematoma, surgical evacuation should be carried out as quickly as possible. The prognosis for neurologic improvement after evacuation depends on the time delay and the degree of neurologic impairment before evacuation.

Cost-Effectiveness of Intraoperative Electromyography to Determine Adequate Screw Position.

STUDY DESIGN: Prospective observational cohort. OBJECTIVES: To examine the cost-effectiveness of IntraOperative ElectroMyeloGraphy (IO-EMG) by evaluating how often an abnormal IO-EMG signal changed the surgeon's surgical plan, or replaced a pedicle screw either intra-operatively or as a second unplanned surgery. METHODS: Patients undergoing instrumented posterolateral lumbar fusion were monitored with intraoperative triggered EMG's. Pedicle screws were placed freehand from L1 to S1 by attending physicians and fellows. Concern for pedicle breach was a screw stimulation<10 mA. RESULTS: There were 145 cases with a total of 725 pedicle screws placed. Mean age was 57.8 ± 14.2 yrs, OR time was 238 ± 95 minutes, EBL was 426.8 ± 354.3cc. Mean number of surgical levels fused was 2.7 ± 1.1. 686 (95%) screws stimulated at >10 mA and 39 (5%) screws stimulated at <10 mA. All 39 screws were removed and pedicles re-examined. Intraoperative screw repositioning was necessary in 8 of 145 cases (6%). No patient required a return to the OR for screw repositioning. As a worst case cost analysis, assuming the 8 patients requiring intraoperative screw positioning would have returned to the OR at a cost of $11,798 per readmission, the per patient cost is $651 which is less than the ION per patient cost of $750. CONCLUSIONS: Only 1% of the 725 lumbar pedicle screws placed in 8 of 145 cases required repositioning. Due to the infrequency of pedicle wall breaches and the cost of ION, the utility of this modality in straightforward lumbar fusions should be critically evaluated.

Predictors of segmental lumbar lordosis following midline posterior (transforaminal) lumbar interbody fusion: Does interbody device type matter?

Background: Controversy exists regarding the ability of posterior (transforaminal) lumbar interbody fusion (PLIF/TLIF) to achieve lordosis. We hypothesized that an interbody device (IBD) designed for positioning in the anterior disc space produces greater lordosis than IBDs designed for straight-in positioning. The purpose of this study is to determine if using either an anterior-position or straight-in position IBD design were associated with successful achievement of postoperative lordosis. Methods: A consecutive series of patients undergoing a undergoing a single-level, posterior open midline (transforaminal) lumbar interbody fusion procedure for degenerative spine conditions during a time period when the two types of interbody devices were being used at surgeon discretion were identified from a multi-surgeon academic training center. Patient demographics and radiographic measures including surgical level lordosis (SLL), anterior disc height, middle disc height, posterior disc height, IBD height, and IBD insertion depth were measured on preop, immediate postop, and one-year postop standing radiographs using PACS. Group comparison and regression analysis were performed using SPSS. Results: Sixty-one patients were included (n=37 anterior, n=34 straight-in). Mean age was 59.8±8.7 years, 32 (52%) were female. There was no difference between IBD type (anterior vs. straight-in) for mean Pre-op SLL (19±7° vs. 20±6°, p=0.7), Post-op SLL (21±5° vs 21±6°, p=0.5), or Change in SLL (2±4° vs. 1±5°, p=0.2). Regression analysis showed that Pre-op SLL was the only variable associated with Change in SLL (Beta = negative 0.48, p=0.000). While the mean Change in SLL could be considered clinically insignificant, there was wide variability: from a loss of 9° to a gain of 13°. Gain of lordosis >5° only occurred when Pre-op SLL was <21°, and loss of lordosis >5° only occurred when Pre-op SLL was >21°. Conclusions: While group averages showed an insignificant change in segmental lordosis following a posterior (transforaminal) interbody fusion regardless of interbody device type, pre-operative lordosis was correlated with a clinically significant change in segmental lordosis. Preoperative hypolordotic discs were more likely to gain significant lordosis, while preoperative hyperlordotic discs were more likely to lose significant lordosis. Surgeon awareness of this tendency can help guide surgical planning and technique.

Perioperative complications with rhBMP-2 in transforaminal lumbar interbody fusion.

Bone morphogenetic protein (BMP) is commonly used as an ICBG substitute for transforaminal lumbar interbody spine fusion (TLIF). However, multiple recent reports have raised concerns regarding a substantial incidence of perioperative radiculopathy. Also, given the serious complications reported with anterior cervical BMP use, risks related to swelling and edema with TLIF need to be clarified. As TLIF related complications with rhBMP-2 have generally been reported in small series or isolated cases, without a clear denominator, actual complication rates are largely unknown. The purpose this study is to characterize perioperative complications and complication rates in a large consecutive series of TLIF procedures with rhBMP-2. We reviewed inpatient and outpatient medical records for a consecutive series of 204 patients [113 females, 91 males, mean age 49.3 (22-79) years] who underwent TLIF using rhBMP-2 between 2003 and 2007. Complications observed within a 3-month perioperative interval were categorized as to etiology and severity. Wound problems were delineated as wound infection, hematoma/seroma or persistent drainage/superficial dehiscence. Neurologic deficits and radiculopathies were analyzed to determine the presence of a clear etiology (screw misplacement) and identify any potential relationship to rhBMP-2 usage. Complications were observed in 47 of 204 patients (21.6%) during the 3-month perioperative period. Major complications occurred in 13 patients (6.4%) and minor complications in 34 patients (16.7%). New or more severe postoperative neurologic complaints were noted in 13 patients (6.4%), 6 of whom required additional surgery. These cases included one malpositioned pedicle screw and one epidural hematoma. In four patients (2.0%), localized seroma/hematoma in the area of the foramen caused neural compression, and required revision. In one additional patient, vertebral osteolysis caused foraminal narrowing and radiculopathy, but resolved without further surgery. Persistent radiculopathy without clear etiology on imaging studies was seen in six patients. Wound related problems were seen in six patients (2.9%), distributed as wound infection (3), hematoma/seroma (1) and persistent drainage/dehiscence (2). Overall, this study demonstrates a modest complication rate for TLIF using rhBMP-2. While perioperative complications which appeared specific to BMP usage were noted, they occurred infrequently. It will be necessary to weigh this incidence of complications against the complication rate associated with ICBG harvest and any differential benefit in obtaining a solid arthrodesis.

Etiology and treatment of cervical kyphosis: state of the art review-a narrative review.

OBJECTIVE: To provide state of the art review regarding cervical kyphosis. BACKGROUND: Cervical spine kyphosis has been increasingly common due to the growing elderly population. Clinicians should comprehensively understand its symptoms, biomechanics, etiology, radiographic evaluation, classification, and treatment options and complications of each treatment. Comprehensive review will help clinicians improve the management for patients with cervical kyphosis. METHODS: The available literature relevant to cervical kyphosis was reviewed. PubMed, Medline, OVID, EMBASE, and Cochrane were used to review the literature. CONCLUSIONS: This article summarizes current concepts regarding etiology, evaluation, surgical treatment, complications and outcomes of cervical kyphosis. Major etiologies of cervical kyphosis include degenerative, post-laminectomy, and ankylosing spondylitis. Clinical presentations include neck pain, myelopathy, radiculopathy, and problems with horizontal gaze, swallowing and breathing. Cervical lordosis, C2-7 sagittal vertical axis, chin-brow to vertical angle, and T1 slope should be evaluated from upright lateral 36-inch film. The most widely used classification system includes a deformity descriptor and 5 modifiers. A deformity descriptor provides a basic grouping of the deformity consisting of five types, cervical, cervicothoracic, thoracic, coronal cervical deformity, and cranio-vertebral junction deformity. The 5 modifiers include C2-7 sagittal vertical axis, chin-brow to vertical angle, T1 slope minus cervical lordosis, myelopathy based on modified Japanese Orthopaedic Association score, and SRS-Schwab classification for thoracolumbar deformity. Current treatment options include anterior discectomy and fusion, anterior osteotomy, Smith-Peterson osteotomy, pedicle subtraction osteotomy, or a combination of these based on careful preoperative evaluation.

Changes in Recombinant Human Bone Morphogenetic Protein-2 Use in Posterior Fusion Over the Past Two Decades.

Background In 2011, studies suggested that complications and cancer rates associated with bone morphogenetic protein (BMP) were greater than previously reported. However, later studies reported complication rates similar to prior literature and no increased cancer rate. We evaluated the pattern of clinical utilization of BMP in posteriorly based lumbar fusion by comparing two periods: 2002-2004 and 2017-2019. Methods Patients who received BMP from 2002-2004 (Early) and 2017-2019 (Late) from a single multi-surgeon institution who had a lumbar fusion were identified. One hundred patients from each cohort were randomly selected. Mean total BMP used at each level and the proportion of BMP placed in the interbody space versus posterolateral gutters were evaluated. Results In the transforaminal lumbar intebody fusion (TLIF) cohort, the total BMP dose in the Late group (6.15 mg) was nearly half of that used in the Early group (12.04 mg, p<0.000). The amount of BMP used in the posterolateral gutters remained similar (Early: 4.01 mg vs Late: 3.38 mg, p=0.222). The amount of BMP used in the interbody space was less in the Late group (2.76 mg) compared to the Early group (8.03 mg, p<0.000). In the posterior spinal fusion (PSF) cohort, the total BMP dose remained similar between the Early (11.96 mg) and the Late groups (10.82 mg, p=0.007). Conclusion Change in the use of BMP in TLIF cases was driven by the complications reported in the literature with no change in outcome. A similar impetus was not seen for PSF.

Return to work in patients with lumbar disc herniation undergoing fusion.

BACKGROUND: Lumbar disc herniation (LDH) is a common problem. When surgical treatment is required, the intervention is typically decompression without fusion. Successful return-to-work (RTW) is a standard expectation with these limited procedures. Occasionally, the size or location of the disc herniation suggests the need for fusion, but the inability to RTW is a significant concern in these cases. The purpose of this study is to determine if the addition of lumbar fusion, as compared to decompression alone, will substantially diminish RTW in patients with lumbar disc herniation. METHODS: This is a longitudinal cohort study using prospectively collected data from the Quality and Outcomes Database (QOD). Patients with LDH, eligible to RTW (not retired, a student, or on disability) with complete 12-month follow-up data, were identified. Standard demographic and surgical variables, patient-reported outcomes (PROs), and RTW status at 3 and 12 months were collected. RESULTS: Of the 5062 patients identified, 4560 (90%) had decompression alone and 502 (10%) had a concurrent fusion. Age and gender were similar in the two groups. The fusion group had worse back pain (NRS 6.52 vs. 5.96) and less leg pain (6.31 vs. 7.01) at baseline compared to the no fusion group. Statistically significant improvement in all PROs was seen in both groups. RTW at 3 months post-op was seen in 85% of decompression cases and 66% of cases with supplemental fusion. At 12 months post-op, RTW increased to 93% and 82%, respectively. CONCLUSION: The need for fusion in LDH cases is unusual, seen in only 10% of cases in this series. The addition of fusion decreased the RTW rate from 85 to 66% at 3 months and from 93 to 82% at 12 months post-op. While the difference is significant, the ultimate deterioration in RTW may be less than anticipated. A reasonable RTW rate can still be expected in the rare patient who requires fusion as part of their treatment for LDH.

Drivers of in-hospital opioid consumption in patients undergoing lumbar fusion surgery.

BACKGROUND: With the current opioid crisis, as many as 38% of patients are still on opioids one year after elective spine surgery. Identifying drivers of in-hospital opioid consumption may decrease subsequent opioid dependence. We aimed to identify the drivers of in-hospital opioid consumption in patients undergoing 1-2-level instrumented lumbar fusions. METHODS: This is a retrospective cohort study. Electronic medical record analysts identified consecutive patients undergoing 1-2 level instrumented lumbar fusions for degenerative lumbar conditions from 2016 to 2018 from a single-center hospital administrative database. Oral, intravenous, and transdermal opioid dose administrations were converted to morphine milligram equivalents (MME). Linear regression analysis was used to determine associations between postoperative day (POD) 4 cumulative in-hospital MMEs and the patients' baseline characteristics including body mass index (BMI), race, American Society of Anesthesiologists (ASA) grade, smoking status, marital status, insurance type, zip code, number of fused levels, approach and preoperative opioid use. RESULTS: A total of 1,502 patients were included. The mean cumulative MMEs at POD 4 was 251.5. Linear regression analysis yielded four drivers including younger age, preoperative opioid use, current smokers and more levels fused. There were no associations with surgical approach, zip code, ASA grade, marital status, BMI, race or insurance type. CONCLUSIONS: Use of preoperative opioids and smoking are modifiable risk factors for higher in-hospital opioid consumption and can be targets for intervention prior to surgery in order to decrease in-hospital opioid use.